Add hosted bus module based on busd

Currently depends on WIP changes to busd to allow in-process clients

sidebus-broker/src/bus.rs

@@ -0,0 +1,71 @@
+use std::sync::Arc;
+use tracing::trace;
+
+pub struct HostedBus {
+    peers: Arc<busd::peers::Peers>,
+    guid: zbus::OwnedGuid,
+    next_id: usize,
+    _self_conn: zbus::Connection,
+}
+
+impl HostedBus {
+    pub async fn new() -> eyre::Result<Self> {
+        let guid: zbus::OwnedGuid = zbus::Guid::generate().into();
+
+        let peers = busd::peers::Peers::new();
+
+        let dbus = busd::fdo::DBus::new(peers.clone(), guid.clone());
+        let monitoring = busd::fdo::Monitoring::new(peers.clone());
+
+        // Create a peer for ourselves.
+        trace!("Creating self-dial connection.");
+        let (client_socket, peer_socket) = zbus::connection::socket::Channel::pair();
+        let service_conn =
+            zbus::connection::Builder::authenticated_socket(client_socket, guid.clone())?
+                .p2p()
+                .unique_name(busd::fdo::BUS_NAME)?
+                .name(busd::fdo::BUS_NAME)?
+                .serve_at(busd::fdo::DBus::PATH, dbus)?
+                .serve_at(busd::fdo::Monitoring::PATH, monitoring)?
+                .build()
+                .await?;
+        let peer_conn = zbus::connection::Builder::authenticated_socket(peer_socket, guid.clone())?
+            .p2p()
+            .build()
+            .await?;
+
+        peers.add_us(peer_conn).await;
+        trace!("Self-dial connection created.");
+        Ok(HostedBus {
+            peers,
+            guid,
+            next_id: 0,
+            _self_conn: service_conn,
+        })
+    }
+
+    pub fn server_guid(&self) -> &zbus::Guid<'_> {
+        self.guid.inner()
+    }
+
+    pub async fn connect_channel(&mut self) -> eyre::Result<zbus::Connection> {
+        let id = self.next_id();
+        self.peers
+            .add_channel(&self.guid, id)
+            .await
+            .map_err(|err| eyre::eyre!(Box::new(err))) // https://github.com/eyre-rs/eyre/issues/31 XXX: busd should not use anyhow!
+    }
+
+    pub async fn connect_unix(&mut self, socket: tokio::net::UnixStream) -> eyre::Result<()> {
+        let id = self.next_id();
+        self.peers
+            .add(&self.guid, id, socket.into(), zbus::AuthMechanism::External)
+            .await
+            .map_err(|err| eyre::eyre!(Box::new(err)))
+    }
+
+    fn next_id(&mut self) -> usize {
+        self.next_id += 1;
+        self.next_id
+    }
+}